This application is based on and claims priority from Japanese Patent Application No. HEI. 3-212392 filed Aug. 23, 1991, the disclosure of which is incorporated herein by reference.
This invention relates to an improvement of a zoom lens system for use with compact video cameras, etc.
The use of compact video cameras is constantly growing these days. Such compact video cameras are usually equipped with a lightweight and small-size zoom lens system of a "two-group" type which comprises, in order from the object side, the first lens group having a negative power and the second lens group having a positive power and which performs zooming by varying the distance between the two lens groups.
However, zoom lens systems of this "two-group" type are limited in zoom ratio and the maximum value cannot be increased beyond about 3. If one wants to meet the requirement of recent versions of compact video cameras for using a zoom lens system capable of achieving a higher zoom ratio, it is necessary to increase the power of each lens group; but then difficulty is involved in correcting aberrations such as spherical aberration and coma, making it impossible to achieve satisfactory optical performance.